Torsion rod suspension for vehicles



Feb. 20, 1951 A. F. HICKMAN TORSION ROD SUSPENSION FOR VEHICLES 6Sheets-Sheet 1 QM M N m mu Mk MW M .3 A WW I W* HAM HHMUUHHHHHHHHMM M MWN h xmwwvkhlgmmx QM .wmx WWN WW kw @NWWNY 95w .Q

Filed May 23, 1946 maoxww av n ATTORNEYS A. F. HICKMAN TORSION RODSUSPENSION FOR VEHICLES Feb. 20, 1951 6 Sheets-Sheet 2 Filed May 23,1946 & wk um mm v. I A ms .I 0/ %N I. a N a v lNVE ATTORNEYS Feb. 20,1951 A. F. HICKMAN TORSION ROD SUSPENSION FOR VEHICLES 6 Sheets-Sheet 3Filed May 25, 1946 SW v v 5 mm & \Q Q ATTORNEYS 6 Sheets-Sheet 4 A. F.HICKMAN TORSION ROD SUSPENSION FOR VEHICLES IIIIIIIII \\\\\\\\\\\\\w'IIIIIII Feb. 20, 1951 Filed May 25, 1946 a at a;

ATTORNEYS GE? (IV 07 Feb. 20, 1951 A. F. HICKMAN TORSION ROD SUSPENSIONFOR VEHICLES 6 Sheets-Sheet 5 Filed May 25, 1946 KvMN kmw E i :1 m9 3 v.

m a @w \M\ @R v INVENTOR ATTORNEYS .7 0 Wm m J w 1111 11%? mi 1|. 115 wk9x a? S? Feb 20, 1951 A. F. HICKMAN 2,542,026

TORSION ROD SUSPENSION FOR VEHICLES Filed May 23, 1946 6 Sheets-Sheet 6ATTORNEYS m M x m 3 wk M/n mi wk bk m wk 9% g.

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4 a 1 l, v 0 g *l fatented Feb. 20, 1951 TORSION SUSPENSION FOR VEHICLESAlbert F. Hickman, Eden, N. Y., assignor to Hickman Pneumatic Seat Co.Inc., Eden, N. Y., a

corporation of New York Application May 23, 1946, Serial No. 671,869

6 Claims. (Cl. 26'757) This invention relates to a torsion rod springsuspension for vehicles and more particularly to such a springsuspension in which the axle is permitted to move against a geometricresilient resistance, both laterally and vertically, relative to thevehicle frame, particularly where the vehicle has a high percentage oflocal variation. While the invention is more particularly described inconnection with a highway vehicle, it is also applicable for use onother land vehicles, such as railroad cars.

This application relates generally to the type of suspension shown in myPatent No. 2,245,585, granted June 17, 1941, for Vehicle SpringSuspension and is a continuation in part of my copending applicationSerial No. 618,917, filed Sept. 27, 1945, for Spring Suspension forRailroad Cars.

In common with my said patent important objects of the present inventionare to provide a spring suspension (1) which will function to safelysupport the car body at high speeds, both when loaded and unloaded; (2)which reduces and cushions both the vertical and lateral impacts fromthe axle against the body of the vehicle, both when the vehicle isloaded and unloaded and without imposing undue end thrusts on thepivotal connections which connect the axles to the body; (3) in whichtorsion rods are employed to provide a longer and variable springresistance range; (4) in which geometric resilient resistance isobtained in a compact structure which requires no lubrication and isfree from the squeaks incident to the use of leaf springs; (5) in whichthe distribution of the load to the body is at a plurality of spacedpoints; (6) in which the side sway is reduced to any desired amount;('7) in which periodic vibration of the suspension is dampered out andin which wheel tramp is avoided; (8) in which all forces are cushionedso as to increase gasolene mileage and decrease tire wear; (9) which haslight unsprung weight; (10) in which the metal stresses are within safeworking limits of heat treated forgings or castings; (11) which can beproduced at low cost and in particular requires only simple machiningoperations; (12) in which the parts are arranged inside of the wheelsand in which the parts are located close to the wheels to provide widepivot positions and increased stability; (13) which is adapted to theuse of rubber springs in place of the metal torsion rods shown; (14)which can easily be taken down and (16) in which auxiliary devices forthe control of side sway are rendered unnecessary; and (17) which isextremely compact and will stand up under conditions of severe andconstant use with .very little servicing.

A specific object of the present invention is to provide a compoundleverage between the axle and vehicle body which provides a doublevariable spring rate.

Another specific object of the present invention is to provide sphericalradial thrust bearings between the frame bracket bearings and thevehicle frame to accommodate flexing of the main lever of thesuspension.

Another specific object of the present invention Fig. 2 is a fragmentaryvertical sectional view thereof, taken generally on line 2-42, Fig. 1.

Fig. 3 is a fragmentary enlarged vertical sec-.

tion taken on line 3-3, Fig. 2.

Fig. 4 is a fragmentary horizontal section taken on line 4-4, Fig. 3.

Fig. 5 is a further enlarged fragmentary horizontal section taken online 5--5, Fig. 4.

Figs. 6 and 7 are further enlarged fragmentary vertical sections takenon the correspondingly numbered lines on Fig. 4.

Fig. 8 is a fragmentary enlarged vertical section taken on line 8-8,Fig. 2.

Fig. 9 is a graph of the action of the spring suspension showing theload on each axle plotted against vertical deflection of the frame.

Fig. 10 is a fragmentary laid out section of axle bracket, shacklestructure and crank arm connecting each end of the rear axle with theframe of the vehicle, this section being taken generally on line lD-l 0,Fig. 8.

Fig. 11 is a continuation of the laid out sectional view shown in Fig.10 and is taken generally on line ll--l I, Fig. 8.

Fig. 12 is a fragmentary section taken on line l2-I2, Fig. 11.

Fig. 13 is a radial section through one of the 3 combined dirt seal,shock absorber and automatic bearing adjuster forming part of the rearwheel suspension, this part being designated at Ill].

The main frame |5 of the vehicle chassis is shown as constituted of theusual pair of longitudinal horizontal side frame bars in the form ofinwardly facing channels |6 which are connected by cross bars IS; Theentire vehicle chassis, together with its spring suspension, is

constructed substantially symmetrically about a vertical longitudinalmedial plane; andhence it is deemed suflicient to confine the followingdescription to the one (left) side of the vehicle, it

being understood that this description applies to the opposite (right)side of the vehicle. Further, the spring suspension at the front end oftheve hicle is somewhat simpler in construction than the rear end, andwill for that reason be described The front. end ofthe chassis issupported on a front axle 20 having wheel brackets 2| at its oppositeends. each carrying the usual kingpin 22 on which the front. wheels 23.are. steerably supported in the usual and well known manner. As bestshown in Figs; 1-4 each wheel bracket 2| is also. formed to'provideanupwardly ex-- tending axle bracket 24, the upper extremity of thisaxle bracket extending horizontally inward toward the vehicle frame l5and being formed at its inner extremity to. provide a tubular hous ing25 for an axle pivot pin 2.6" which can be journalled therein in anysuitable manner. Thistubular housing 25 and the axle pivot. pinjournalled therein extends horizontally transversely of the axle 20 andhence lengthwise of the vehicle frame I5.

The opposite ends of each axle pivot pin. 26 project from the tubularhousing 2.5 and are. connected, as best shown in Fig. 4, by shackles 28and 29 with the corresponding ends of a crank arm pivot pin 36. As bestshown in Fig. 5,.thi's crank arm pivot pin 30. is journalled in. a pairof bearings 3| in a tubular housing 32v provided atthe free end of acrank arm 34. Each of the bearings 3| is preferably in the form. of abushing 35 of. bearing material impregnated withlubricant and encased ina metal sleeve36which is pressed into the corresponding end of the borethrough the tubular housing 32. The crank arm 34 is shown as being inthe form of two spaced arms 38 extending inwardly from the crank armpivot pin 30 and have cylindrical ends 39 which embrace and are weldedto a tube 4'0which serves as afulcrum for the crank arm 34. This fulcrumtube 4|] for the crank arm 34. is journalled on. the main frame of thechassis: as hereinafter described. The axes of the axle pivot pin 26,crank arm pivot pin 30 and crank arm fulcrum tube 40 are substantiallyparallel extending horizontally above and transversely of the front axle20 so as to extend lengthwise. of the vehicle frame.

It will be noted that the shackles 28 and 29 connecting the oppositeends of each axle pivot pin 26 with the ends of the crank arm pivot pins30 are of different construction. Thus: each shackle 28 is in the formof a forging embracing the corresponding ends of the axle pivot pin andcrank arm pivot pin and welded thereto as in'-- dicated at 4.2. Aroundeach of these pins 26, 30 the shackle 28 is provided with an enlargedcup"- shaped cylindrical bore 43 which, as best shown in Fig. 5, fitsaround the corresponding end of the tubular housing for thecorresponding pins 26,. 30. A thrust bearing 44 is shown as: secured 4in the inner extremity of each of these pockets 43 and as bearingagainst th opposing end face of the corresponding tubular housing 25, 32for the pins 25, 30. As with the bearings 3| each of these thrustbearings 44 is preferably made of a lubricant impregnated material andis shown as being in the form of a washer held in a metal holder whichin turn is pressed into. the corresponding cup-shaped bore 43 of theshackle. An annular dust seal 45 is also preferably provided at theouter extremity of each of the cup-shaped bores 43.

The opposite shackle 29 is composed of a plurality of laminations 68'ofspring steel each having opposite openings fitting around the hub 49 ofa cup-shaped inner nut 50 which is screwed on the threaded ends of theaxle pivot pin 26 and crank arm pivot pin 30. Around each of these pins26, 30, the cup-shaped inner nut 50 is provided with an enlargedcup-shaped cylindrical bore 5| which, as best shown in Fig. 5;fitsaround' the corresponding end of the tubular housing for thecorresponding pin 26.; 30'. A thrust bearing 52 is shown as secured; inthe inner extremity of each of these pockets 5| and'as bearing against:the opposing end face of the: correspondingtubw lar housing 25, 32 forthe pins-25,; 3| As, with thebearings 3| each of these-thrust; bearings:52

preferably made of a lubricant impregnated ma terial and is shown:asbeinginthe form. of a washer held in a metal holder: which in turnpressed into the corresponding cup-shaped bo-re 5| of the cup-shapedinner nut 50. An annular dust seal 53 is also, preferably provided at:the

outer extremity of eacho-f the cup-shaped bores 5|.

Th laminations 4-8 are shown. as retained on the hubs or necks 49 of thecup-shaped inner."

nuts 5|] by end nutsv 55 also, screwed on. the

threaded ends of thepivot pins 26; 30. These.

each supported on the corresponding side beam;

|6 of the vehicle frarr -iev by. apair. of bearings 5.8. and 59. For thebearing 58 the fulcrum tube lll: has welded theretoametal bushingfidwhichis;

. fitted inthe bearing 6|, this bearing beingprefeerably madeof abushingof lubricant impregi nated material fitted in a'metal sleeve:which.is in turn pressed in the bore'of a bearing housing; or bracket 62which canbe secured tothe corresponding longitudinal, side; bar It ofthe chassis in any suitable manner. Preferablyannulardust seals .63. arearranged on: the: bearing housings at opposite ends of the bearings 6|.

Each bearing 59- is arranged on the opposite: side of the crank arm 34from; the bearing: 58- and includes a metal bushing 65- welded on/the;fulcrum tube and fitted in a bearing 55, this bearing also beingpreferably made of a bushingof lubricant impregnated materialfittedin.-a metal sleeve which is in turn pressed in the bore-of a bearinghousing or bracket 68wh-ich can be see. cured to the correspondinglongitudinal side bar |6of the chassis in any suitable manner. Pref-'-erably annular dust sea-ls Ell-are arranged; in the. bearing housingsBeat the opposite ends: ofthebearings 63,6.

A socket member 10 is welded to the forward? end of each of the fulcrumtubes: 40 and this socket member is provided with an oversize ovalledbore H in which i'slo'osely fitted the-ens:

larged ovalled live end I2 of a torsion rod 13. This live end of thetorsion rod is also pinned to the socket member by a transverse pin 14loosely fitted in a hole extending therethrough. Each torsion rod l3extends coaxially through the corresponding fulcrum tube 40 and has anenlarged ovalled dead end 75 loosely fitting in an enlarged ovalled bore16 provided in an anchoring socket member '53. The opposite ovalled ends12, 15 of each torsion rod and the ovalled sockets H, 16 therefor arepreferably formed in accordance with my Patent No. 2,213,004 grantedAug. 27, 1940 for Torsion Rod Mounting.

The dead end 15 of each torsion rod 13 is adjustably anchored againstrotation and for this purpose, as best shown in Figs. 6 and 7, theanchoring socket member 18 is shown as being generally in the form of acylinder with an integral adjusting arm 73 extending horizontally andradially therefrom as best shown in Fig. 7. The cylindrical socketmember it is shown as held in a semi-cyclindrical groove provided in theunderface of a block W by a U-bolt 81. This U- bolt preferably is seatedin a circumferential groove in the cylindrical socket member 18 to holdit against endwise displacement and its legs preferably straddle thesocket member 18 and block 8!! and are anchored in the correspondingside bar [5 and adjacent cross bar 18 of the chassis frame to hold thissocket member and block in position.

The free end of the adjusting arm 19 is supported by an adjusting nut 82and lock nut 83 on the lower end of a bolt 84 which extends through thisadjusting arm. The upper end of this bolt is anchored in the adjacentcross bar l8 of the chassis and it will be seen that adjusting the nuts82, 83 up or down serves to adjust the radial position of the dead end15 of the torsion rod and hence adjusts the normal positions of thelinkage connected to the live end 12 of the crank arm as well as thenormal elevation of the chassis frame is with reference to the ground.

A feature of the present invention resides in the elimination of thrustbearings between the frame and the crank arms and fulcrum tubes 49.Since adequate thrust bearings 44 and 52 are provided for the axle pivotpin and crank arm pivot pin 3@, it will be seen that a l thrustlongitudinally of the chassis derived from drive and brake torquereactions are carried directly to these fulcrum tubes. As long as thereis any downward load on the suspension, this thrust is transmittedthrough the friction of the live end 12 of the torson rod in the ovalledsocket ID to the torsion rod and from the torsion rod through thefriction of its dead end '55 in the socket 18 to the anchoring block 89,thereby to eliminate the need for large thrust bearings at the framejournals for the crank arms 34. When the body is thrown upwardly so thatthe suspension is unloaded, any fore and aft thrust forces are carriedthrough the torsion rods to their anchorages by the pins 74, which areloose in the oversize holes in the torsion rods so as not to functionnormally to resist thrust. It is also desirable to have a stop at therear end of each fulcrum tube 4!] to take care of any excessive rearwardthrust at the frame journal for each crank arm 34. For this purpose anL-shaped stop member 86 is shown as bolted by bolts 38 to the rearbracket or bearing housing 68 and as having its free end in position toengage the end of the corresponding fulcrum tube 50 should any suchexcessive thrusts develop. These bolts 88, as best shown in Fig. 6, alsocarry a pair of metal bands permitting the necessary rotary movement ofthe adjacent part of the torsion rod 13.

The rear end of the chassis frame it is supported by a drive axlehousing in turn supported by dual wheels 96 at its opposite ends.

As best shown in Figs. 2, 8 and 10 a U-shaped axle bracket 98 is fast toeach end of the axle housing 95, this axle bracket having horizontalarms 99 extending fore and aft, of the rear axle housing and havingupwardly extending extremities I60. These brackets are fixed to the axlehousing 95 immediately inside of the drive wheels 96 and, upon referenceto Fig. 8, it will be noted that these extremities slant inwardly ortoward the side bars I5 of the chassis frame instead of being verticallydisposed.

The upwardly extending arms or extremities I00 of each axle bracket 98carry an axle pivot pin [0| which, as best shown in Fig. 10, has a head[02 at one end in which is welded a pin I03, this pin projecting into agroove in the adjacent axle bracket arm I00 and to prevent the axlepivot pin I ill from turning. A loose pin is can be provided between theopposite end of the axle pivot pin H1! and the opposite arm Hit of theaxle bracket to prevent relative rotation of these parts and the axlepivot pin can be retained in position by a nut I535 threaded thereon.The headed end of the axle pivot pin it! can be mounted in thecorresponding arm Hit) of the axle bracket 98 through a sleeve orbushing I08 having a radial enlargement at its inner end to provide athrust bearing face, the thrust against this enlargement beingtransmitted to the head I132 of the axle pivot pin. The opposite end ofthe axle pivot pin is carried by a sleeve or bushing Hi8 having a radialenlargement at its inner end to provide a thrust bearing face, thisenlargement being disposed in engagement with the adjacent arm Hill ofthe axle bracket 98. The threaded end of the axle pivot pin llll whichcarries the nut I05 is reduced to provide an annular shoulder I59bearing against the thrust bushing or collar 188.

Each axle pivot pin ill! carries a plurality of bearing bushings 1 lil,each preferably being made of lubricant impregnated material held in acylindrical metal shell. These bearing bushings are fitted in theopposite end of the bore l i l through the tubular cross part H2 of ashackle structure H3. Shackle arms 5M are integrally formed with theopposite ends of the tubular cross part H2 of the shackle structure andthe opposite ends of these shackle arms carry a crank arm pivot pin H5.One end of this crank arm pivot pin H5 is provided with a head He inwhich is welded a pin H8 fitting in a groove provided in the adjacentshackle arm I it so as to prevent the crank arm pivot pin from turning.The headed end of the crank arm pivot pin H5 is mounted in the armthrough a sleeve or bushing H9, this being similar to the sleeve orbushing H36 and having a radial enlargement at its inner end to providea thrust bearing face, the thrust against this enlargement beingtransmitted to the head H4 of the crank arm pivot pin. The opposite endof this crank arm pivot pin H5 is'carried by adjacent end of the crankarm pivot pin I I5 -is reduced'to provide an annular shoulder I22bearing against the thrust bushing or collar W255 and is threaded toreceive-a nut I23 which bears,

through a suitable lock was-her, against the-outer face of theadjacentshackle arm IIfi.

The crankarm'pivot pin I I5 carries a pliirality of bearing bushingsI25,thes'e bearing bushings preferably being identical with 'the bearingbushings [I and being made of a lubricantimpregnated 'material containedwithin a cylindrical metal shell. These bearing bushings I25'are='fitted 'in the opposite 'end's'of a bore I26 through thecylindrical offset portion'IZS of a crank 'a'rni indicated generally atI29. While this crank arm can be made of Welded tubing, it is shown asbeing in the form of a tubular forging or casting.

In each of these coaxial fulcrum ends ISI of the crank arm !29 ispinned, as indicated at I33, the stem I34 of a ball I35, the pins I33preferably being tapered and held in position by nuts I35, as best'shownin Fig. 8. The stems I34 are co axial and the balls I35 are disposedaxially outward from the coaxial fulcrum ends I3! of the crank arm I29and form part of ball and socket bearings, indicated generally at I38which fulcrum each crank arm I29 on the longitudinal side bars I of thechassis frame.

Each of these ball and socket bearings I38, as best shown in Fig. 8,includes a housing or casing I 3'! which can be secured to the side barI5 of the chassis frame in any suitable manner and which has an axialbore extending therethrou'gh with an enlarged threaded end adjacent thecrank arm I29 and a reduced threaded end at its onposite end. screwed aplug I49 carrying an end thrust bearing I39 which is shown as being madeof lubricant impregnated material in a metal shell and having a concaveface fitting the axial end of the ball -I35. The sides of the ball I35are engaged ting the circumference of the ball I35, the metal shell ofthis bearing being fitted in the bore of theb'ear'ing housing I35. Thisbearing 'I4I is held in position by an externally threaded ring IE2screwed into the large threaded end of the bore through the housing I39and a dust 569.1 I 43 is preferably interposed between this retainingring I42 and the stem 3 1 of the ball I35.

As best shown in Figs. 1,2, 8 and 10, an arm I45 is formed integrallywith the fulcrum portion of each crank arm I29 at one extremity I3Ithereof and normally projects downwardly and inwardly therefrom. As bestshown in Figs. 8 and 1'1,'the outer or lower end of this arm I45 isformed to provide a horizontal bore extending transversely of the axleor lengthwise 0f the chassis and having a shackle pin I45 journalledtherein. For this purpose a pair of bearings I41 are arranged in thisbore to journal the pin I45, each of these bearings preferably beingmade of a bushing of lubricant impregnated material encased in acylindrical sheet metal sleeve.

The opposite ends of each pin I 46 is reduced to provide an annularshoulder I48 and threaded to receive a retaining nut I49 and a laminatedshackle I59 is held between each nut I49 and shoulder Hi8. For thispurpose a wear washer I5] -is provided between each nut I49 and the Inthis reduced threaded end is t adjacent cuteriaminauon cfthe-corresponding v shackle 'I5B' a1id a' wear Washer 452 is prov'idetlbetween eacushoumer I48 and the adjadeiit innor-lamination or the corresonding Shackle I 5. To -provide -a-dust seal "for the bearings I4! aring I 53 "of i-ubbr O'r other Soft -resili'entjplas'tic material isheld in a 'compressed -c'ondition betw en each 'ifih'er lamination ofthe shackles I55 rid the opposing face or the arm I -arou'ndtliepin-I46. n

The sha'ckl'es '1 5 0 exteridg'enerally herizohtally inwardly from "eachshamue pin F46, best shown in Fig. 8 and the inner'extrefii-ities' ofeach pair of these shackles is pivotally secured to the lower end of anarm I55 a similar manner. As the pivotal connection betweh tlie shacklesI and this arm I iside'ntical to' the pivotal connection between theseshackles and the arm I45, the same "reference numerals ve been employedand the description is n'ot re peated.

'Eacharm I5'5 is substantially-longer than the corresponding arm I45 andextends upwardly and-outwardly from its shackle pin Hit-generallyparallel with the ar rn I 45, as best 'shtiwh Fig. 8. The upper end ofeach arm 155 is fulcrumed on' the'side bar I6 o'f tl-iefrani'e I5 on anaxis above and preferably --slightly inward from the fulcrum axis of thearm I45. For this purpose, as best shown in Fig-11, the upper 61 fulcrumend of the arm I55 is fas't to a fulcrurn sleeve I55 by 'mea'ris'of-acr'bss pin '-'I58 arr-d kes I59. This fulcrum sleeve T56 isjouriialled ih a A air b'f bearings IE0 at opposite ends 'fther e bf,

th'se bearings preferably birig in the fdr ifl' o f a sleeve oflubricant impregnated-material encased "a shell and the shell of eachbearing being fitted-in the bore 'ofa bearing housing IE-I. Each'pair ofbearing housings I61 is shown as secured "to an L-s'haped anchoringbracketflfl and one leg of this anchoring bracket I62 is secured to theadjacent web of the adjacent longitudinal channel beam I6 0f the chassisframe I 5 while the other leg of this anchoring bracket IE2 is securedto the web or an adjacent crosschannelbearn I8 of the chassis frame.

Each fulcrum sleeve I56 is provided with ovalled bore I 63 in which isfitted the enlarged ovalled live end I65 'of a to'rson rod I66, rues-eparts being preferably formed in aecerdan'cewith my said Patent No.2,213,004. "This t'dr'sion "rod extends forwardly through an opening [aspro-- vided in the adjacent side-flange of the cross beam I8 and thedead end I59 can be anchored on the chassis "frame in any suitablemanner, these rear torsion rods I66 extending generally as shown bydotted lines in Fig. 2.

A feature-of the invention resides in the forth and mounting for thecornbined'rubber dirt seal, shock absorber and automatic bearing adapterillustrated in Fi 13. "This is in the form of a ring I10 of rubber orlike soft, resilient plastic material and having a concentric btire I1 Isome what larger than the enlarged parts of each axle pivot pin IIII andcrank arm pivot pm I I5. At one side this ring is provided with anaxially extending peripheral flange I12 and its op'pbsite sideis'p'rovi'ded with a series of concentric annular grooves or flutes [15.One bf thes'e'rings I10, as best shown'in Fig. 10, is fitted over eachend of each crank arm pivot pin I'III and crank arm 1 pivot pin I I5 andis interposed between the tubular housing for this pin and an adjacentthrustlargement of the corresponding thrust sleeve I05,

Operation In the operation of the suspension, the upward movement of oneend of the front axle 29, through its shackles 28, 29, swings the outeror offset portion 32 of its crank arm 34 upwardly, the fulcrum tube 40of this crank arm oscillating about its bearings 58 and 59 in thebearing housings 62 and 68, respectively. This rotation of the crank arm34 and its fulcrum tube 49 is yieldingly resisted by the torsion rod I3which has its live end 12 ovalled and fitted-in-the ovalled socketmember fast to the front end of the corresponding fulcrum tube 40', andhas its dead end I5 anchored in the socket member 18. The front torsionrods 13 thereby provide the springs for supporting the front end of thechassis frame I5.

Similarly the upward movement of one end of the rear axle housing 95,through the shackle arms I I4 of the shackle structure H3, swings theouter or offset portion I28 of its crank arm I29 upwardly, this armswinging about its ball and socket bearings I38 carried by the chassisframe. This rotation of the crank arm I29 is yieldingly resisted,through the arm I 15, shackles I59 and arm I55 by the torsion rod I55which has its live I end I65 fitted in the ovalled fulcrum sleeve I56for the arm I55 and its dead end I54 anchored in the chassis frame. Thetorsion rods i 66 thereby provide the springs for supporting the rearend of the chassis frame I5.

It will be noted that the shackles 28, 29 are inclined upwardly andinwardly from thecrank arm pivot pins 30 to the axle pivot pins 25 andthat similarly the shackle arms H4 of the shackle structure H3 areinclined upwardly and inwardly from the crank arm pivot pins I '5- tothe axle pivot pins IIJI. This upward and inward inclined arrangement ofthese shackles tends to cause each axle to centralize itself in adirection transverse of the chassis and enables th action of gravity togeometrically and resiliently resist any such movement of the axle awayfrom its central position. This permits the vehicle body to movesubstantially straight ahead despite a certain amount of lateralmovement of the axle. This arrangement of the shackles further provideshigh and wide pivot positions which provides increased stability in thatit provides effective spring centers which can be as wide or wider thanthe track of the vehicle. Further, this arrangement of the shacklesreduces sidesway,-

the high and wide pivot positions, together with the upward and inwardslant of the shackles, providing a suspension in which the vehicle bodyis more nearly suspended than mounted. Other important advantages whichflow from the inclined arrangement of the shackles shown are thereduction in the possibility of wheel tramp and in the elimination ofthe need for anti-body-roll devices, such as torsion bar stabilizers.

When one end of the front axle 20 is so forced upwardly relative to thechassis, the effective resilient opposing force of the torsion rods 13increases at a geometric and not at an arithmetic rate. In thisparticular case the geometric rate is .of the accelerated increase typein which inl0 crements of vertical movement of the front axle areopposed by an accelerated rate of resilient resistance. This isprimarily due to the progressive decrease in the effective leverage ofthe crank arms 34 as they swing upwardly and inwardly about the torsionrods 13 as axes of rotation. This action is also influenced by thevarying angularity of the shackles 28, 29 and the fact that incrementsof vertical displacement of the pivot pins 30 cause accelerated rates ofincrease in the angular displacement of the torsion rods I3. This latteris due to thefact that increments of vertical movement of said pivotpins 30 are not proportional to the'accompanying increments of angulartwist to which their companion torsion rods 13 are subjected.

This geometric action also occurs when the front axle moves downwardlyrelative to the chassis from the normal position shown in Fig. 3.

Throughout this particular movement the geometric action is of theaccelerated decrease type,

that is, as the front axle passes through increments of downwardmovement, the rate of decrease of the resilient force tending to pushthe axle downwardly decreases.

By this means, so far as vertical forces are concerned, the vehiclechassis is free to float along solely under the influence of gravity(plus whatever vertical momentum forces are present), this feature ofthe invention being of particular significance when it is realized thatthe load carried by the vehicle is also, at this timeysolely under theinfluence of gravity (plus whatever vertical momentum forces arepresent).

The consequence is that, within this particular range of movement, theload in the vehicle moves vertically upand down with the sameacceleration and deceleration as'the body and hence without changing thepressure between the load and the body. Such a desirable result is quitedifferent from that obtained from the conventional leaf springsuspension in which the axle and the rest of the unsprung weight dragsor jerks down the body whenever the strains imposed on the chassis arenegative. In the present front end suspension no such negative force,tending to pull the body downwardly, is possible.

Since the linkage between the rear axle 95 and the chassis frame isgenerally similar to the linkage between the front axle 20 and thechassis frame, it will be seen that the above discussion applies withequal force to the rear end suspension, the action of the rear endsuspension being modified, however, by the use of the arms I andshackles I59 to connect-this linkage to the torsion rods I66.

One of the principal'features of the present invention resides in'the-action of lever I connected as shown in-Fig. 8 to produce theperformance curve shown in Fig. 9. It will be noted that the normalpivot positions of the axle pivot pin IIlI, crank arm pivot pin H5 andcrank arm fulcrum I34 are in the same position as the correspondingparts 26, 39 and 45 of the front end suspension andhence action of thesuspension from the rear axle up to the crank arm I29 is the same as theaction of the front end suspension from the front axle 20 up to thecrank arm 34.. However, the arms I45 and i55 connected by the shacklesI5!) are not a mere relay structure leading to the torsion rod I56. Inparticular it will be noted that the greater length of the arm I55 ascompared with the arm I45 and the arrangement of the pivots for thesearms result in these arms modifying the action acre-mice 11 of the crank'arni- *E ZQ in's'tead: of being merely a motion transmitting mechanism;or relay to a remotely located torsion rod.

For convenience in describing this action of the rear end suspension,the pivot axis of the axle pivot pin it is designated in Fig. 8 at A;the pivot axis of the crank-arm pivot pin I 1 5" is designated at B; thepivot axis of the to. pins I34 for the crank arm is designated at C;

the pivot axis of the shackle pin M8 for the arm I45 is designated at D;the pivot axis of the shackle pin M6 for the arm I55 is designated atE'; and the pivot axis of the fulcrum sleeve 1'56 andof the torsion rod'I66 is designated at F.

With the rear: end suspension constructed as shown in Figs. and 11, itwill. be seen that when a load isapplied to the frame I5 causing springdeflection, pivot C will move downward causing the effective length ofthe lever C, B to become shorten Thus the lever C, B has its greatesteffective length, as against vertical forces, when it is in thehorizontal position shown in Fig. 8 and this effective lengthprogressively decreases as this lever departs from this position. Sincethis lever 'arin C, B decreases in eifective length, and hence has lessinfluence on the supporting torsion rod I66, as it is displaced by aload or vertical impact on thechas'sis, it provides a variable ratesuspension. In other words, increments of load on the chassis cause aprogressively decreased spring deflection so far as the lever C, B isconcerned.

It will also be "seen that when" this load is applied to the chassis,the effective length of the lever. C, D increasesas against the opposingforce exerted by the shackles I50. lhus the clockwise rotation of thearm I55 under increments of load causes this arm I45 to be broughtprogressively more perpendicular to the line of force connecting thepivots D; E and hence the efiective length of the lever C, D increases.It will also be seen that when this load is applied to the chassis; theactual distance between the point C, E decreases. Thus with theclockwise rotation of the arm M5 under load, the pivot E is drawn closerto the pivot C so that the distance between these pivot points becomesshorter.

When the chassis I5 is raised s'uiiiciently high to completely unloadthe torsion rod 1-66 at pii ot F, the pivot D at the end of thelever'arm Hi5 moves to the position indicated at G and the pivot E atthe end of lever arm 3'55 moves to the position indicated at H. It willbe noted that in this unload-9d condition of the torsion ro'd res,the'p'ivots C, D and: E are in a straight line represented by the lineG, H. When this straight line relationshioG', H of the pivots C, D, Eobtains, it will be seen that the torsion rod $63 is at infinitedisadvantage to resist any fo'rce created around pivot c and acting onlever arm its. T-hus the lever arm 1'45 and. shackles lee havestraightened out and the torsion rod 555 and lever arm I55 are incapableof resisting rotation of the lever arm I45 around the pivot C and hencethis lever arm I45 is free to move. This condition is represented at thestart of the curve shown in Fig. 9.

When the empty body is released from this position to load therear'torsion rods, the linkage assumes the full line position shown inFig.8. In this movement the pivots C, D, E move out of the straight lineunloaded relation indicated by the line G, H and assume the triangulararrangement shown with the pivots C, D, E in the obtuseangled triangleshown. In this position the tor- 12 sionrod T66 no longer is incapable"of resisting forces created around thepiv'Ot C since the lever I5 hasincreased its elfective length from zero (its position at G) to arelatively short effective length where the line of force directedagainst its pivot D (represented by the axes of the shackles !50) is atobtuse angle to the plane of the pivots C, D. Because of the stillrelatively short eiiective length of the lever arm I45, and because thecrank arm I29 is at its maximum effective length, the load becomes veryeffective oh" the torsion rod and the weight of the empty body, which isassumed to be 1,500 pounds on each rear spring, causes, as illustratedon the graph, Fig. 9, 2%; inches or vertical deflection of the chassisI5 relative to the ground out of a total possible deflection of 6 /2inches. This pr ov ides an empty body ride which is comparable to fullload ride.

when the chassis is is loaded the pivot E moves to position I and thepivot D moves 'to position J, as illustrated in Fig. 8. In this movinent the pivots C, D, E move out of the obtuseangled triangle shown andassume the almost right-angled triangle arrangement represented by thepoints C, -J, I. In this position the lever 'arm I45 is close to itsmaximum effective length but the effective length of the crank arm I29,and the leverage between pivots C and E have been reduced, the crank armI29 having been moved close to the position where the line of pressureimposed by the axle against the crank pin H5 or pivot B is able to passthrough the axis "or pivot C of the crank arm I29. This latter 'ist-henon-bottoming position of the linkage since when the pivots A, B and Care in straight line relationship the spring resisting the rotation ofthe crank arm I29 is at infinite advantage to resist upward movement ofthe axle. In this loaded position of the chassis the ride is comparableto the empty body ride.

The performance of the spring suspension as shown on the graph, Fig. 9is therefore the result of the varying effective lengths of the leversconnecting the axle with the torsion rod and the varying positions ofthe pivots of these levers. As shown on this chart the empty body,assumed to be 1.500 pounds per spring, causes 2 inches of springdeflection measured by the distance from the chassis to the ground. Asincrements of load are added, the changing effective length of thelevers and changing, pivot positions increasingly favors the torsion rodI 66 so that with an added load on each spring Of 4,500 pounds, or 300%,only 2% inches of added spring deflection occurs, this being representedby the intersection of the 6,000 pound line with the 5 inch deflectionline on the chart. When the total load on. the body increases to 9,000pounds, representing an increase of 50% from this 6,000 pounds lload'edis approximately the same as the full load ride,

the suspension being thereby particularly advantageous in vehiclessubject to a large percentage of load variation. The suspension is alsopartic ularly advantageous Where top heavy loads are carried and Where aminimum change in body through the arms of the shackle structure I I3,

and also adequate sidesway control. This sidesway control is due to thehigher rate of spring deflection when loads are applied; the wide andhigh axle pivots A; the upward and inward slanting of the arms I44 ofthe shackle structure H3;

and because the axle pivots A do not go down when loads are applied.Since these axle pivots A remain at constant height when the body goesdown under load, the axle pivots rise relative to the body when a loadis applied so as to improve their sidesway control under loadedconditions.

A feature of the invention also resides in the use of the sphericalradial thrust bearings I38 to journal each crank arm on the frame !5 ofthe vehicle, as best shown in Fig. 10. While in some cases rubber framejournal bearings could be used to provide a similar action, for heavyloads it is desirable to provide the spherical friction bearings shown.which require no lubrication due to the fact that the bearing surfacesengaged by the balls are made of a lubricant impregnated material. Theprimary purpose of these spherical j radial thrust bearings is toaccommodate the flexing of the crank arm l29.

Where loads as much as 18,000 pounds per axle are applied, a thrust,longitudinally of the chassis, of as much as 5.400 pounds from each axleand to the bearings 138 are encountered. To handle this thrust loadwithout radius rods each of the bearings I38 is in the form of a balljournalled in a radial bearing and exerting thrust forces against thethrust bearing I39 inserted in the metal plug I40. the lever arm I29 totwist under the heavy loads imposed upon it with out misalinement of itsbearings and also provides an economical and practical bearing forresisting the heavy longitudinal thrust forces which develop between theframe and axles of heavy vehicles. I

A further feature. of the rear end su pension resides in the use o thecombined dirt seal. shock absorber and friction re ulator or automaticbearing adjuster shown in Fig. 13 in the manner shown in Fig. 10 andwhich also allows the shackle bolts and nuts to be tightened to a predetrmined metal-to-metal stop with reasonably broad machine tole ances forall metal parts.

In acting as a dirt seal, s nce the rub er is molded th the flutes I13on one or both sides, a low initial rate of co re sion is establishedfor any direction. After the flutes I13 have flattened jump in thecompression rate insures mainta ning the dust sea s at both ends of thepins l! and H when the assembly is subiected to end thrusts. Thus when aheavy thrust load is applied to the rubber seal H0 at one end of theassemblv, the opposite rubber seal I must ex and a sufficient amount toinsure against any opening from the pin bearings to the atmosphere. Thisexpansion is insured by the high rate of compression encountered in thecompressed rubber seal after its flutes have been flattened out.

Another important advantage of the flutes I13 on the rubber disks H0 isthe fact that rubber, especially the present synthetic rubbers, takes apermanent set over a period of years of 40% or more. The flutes permitthe assembly of the sus- The use of ball and socket bearings permitspension with sufficient precompression on the rubber disks H0 toanticipate the permanent set and also to withstand the brake thrustreactions without heavy static thrust loads on the end bearings. Thefluted design of the disks I10 makes the unit foolproof in assembly orreassembly because it is merely necessary'to tighten the nuts of theshackle pins l0l, H5 to a dead stop after which they are locked in placeby the cotter pins.

In acting as shock absorbers, because of th precompression of the disksI!!! a predetermined pressure is at all times imposed between the lthrust bearings for the shackle pins llll, H5 and the shackle and axlebrackets, respectively. vAny substantial degree of rotation of theshackle bracket is thereby resisted by the friction imposed by therubber disks I10. On the other hand with slight vibrations or movementsof the shackle structures the rubber disks I10 will flex torsionallyaround the shackle pins before the resistance of the rubber issufficient to cause action of the friction thrust bearings. By thismeans the vehicle is resiliently free from friction for the smallirregularities in the road to provide a friction free boulevard ride,and at the same time the rubber'disks I10 act to check frictionallymovements caused by large irregularities.

A further feature of the invention resides in the use of the sphericalradial thrust bearings I38 at the ends of the crank arms. Where flexingof these crank arms is encountered, it is desirable to use either rubberframe journal bearin'gs or spherical friction bearings as shown. The

' out the compre sion rate jum s very high. This vehicle shown isdesigned to accommodate loads of as much as 18,000 pounds per axle. Thiscreates a thrust load, under brake reaction lengthwise of the frame, ofas much as 5,400 pounds at each end of the axle. To handle such thrustload without radius rods the spherical bearings shown each has a thrustbearing I39 inserted in a metal plug I40. This provides a verypractical, economical and readily adjustable .means of handling theheavy longitudinal forces present in heavy duty vehicles without restorting to radius rods.

Another feature of the invention resides in the use of the torsion rodsto eliminate thrust bearings. It will particularly be noted that theusual thrust bearings on the frame journal pivots have been eliminatedand instead this thrust is transmitted to the anchored ends of thetorsion rods. In setting up the suspension, for example the suspensionshown in Figs. 1-'l, the torsion rods have had holes jig drilled intheir ovalled ends to fairly accurate dimensions between centers and areloosely anchored to the frame. These holes in the ovalled ends of thetorsion rods are drilled at least inch over size of the pins or boltswhich they receive. These oversize holes match up with holes in theovalled sockets or receptacles 10, 18. The bolts or pins 14, 85. aresnugly fitted in the holes in these ovalled sockets or receptacles l0,18 but have a substantial clearance in the holes through the ovalledends of the torsion rods so as to permit the ovalled ends of the torsionrods to rotate in their ovalled sockets a sufficient amount to effectanchorage in the ovalled sockets without any shearing action or force onthe bolts or pins 14, 85. The frictional engagement between the ovalledends of the torsion rods and the ovalled sockets of the socket 1 thrustbearingsin the frame journals. 1 7-4, 85 only become effective againstsuch thrusts age. :for the torsion rods, no part of :this and Y thrust:being transmitted through the :pins 14,135.

its unsprung portion. Thus as long-as the sprung weight is partiallysupported on the unsprung portion of the vehicle the friction betweenthe torsion rod ends and its sockets or receptacles ll], .18 is morethan sufiicient to insure the unsprung weight against shiftinglongitudinally of the vehicle, thereby to eliminate thenecessityfor Thepins when the unsprung weight of the vehicle is tossed "so as tocompletely unload the unsprung portion thereof as when passing over aculvert at high speed.

The advantage .of eliminating thrust bearings for the frame journals is,of course,:ob-

' rom the foregoing it will be seen that the present invention providesa suspension, especially for heavy duty vehicles having a "highpercentage of load variation, having many operating advantages,particularly in the double variable linkage used at the rear end of thetruck. The suspension also eliminates frame journal thrust bearings,provides a unique combined rubber dirt seal, shock absorber andautomatic bearins adjuster and provides a unique bearing structure forthe main crank arms which permits flexing and at the same timeadequately withstand both radial and end thrust impacts.

I claim as my invention: 1. A vehicle spring suspension for connectingthe frame and wheeled axle of a vehicle compris- :ing a normallygenerally horizontal crank arm fulcrumed on said frame on a generallyhorizontal axis extending transversely of said axle and free to movelengthwise of said axis, a shackle mov- -ably connecting the free end ofsaid crank arm with said axle, and means for restraining rotative' andaxial movement of said crank arm relative to said frame, comprising atorsion rod having ends which are out-of-round in cross section andarranged generally in alinement with said axis, a socket member fast tothe hub of said crank Jar-m and having an oversize out-of-round socketfitting one out-of-round end of said torsion rod, an anchoring socketmember fast to said frame and'having an oversize out-of-round socketfitting the other out-of-round end of said torsion rod and means pinnineach of said socket members to the corresponding end of said torsionrod. 2. A vehicle spring suspension for connecting the frame and wheeledaxle of a vehicle, comprisa normally generally horizontal crank armfulcrumed onsaid frame on a generally horizontal axis extendingtransversel of said axle and free to move lengthwise of said axis, ashackle i .movably connecting the free end of said crank arm with saidaxle, and means for restraining rotative and axial movement of saidcrank arm relative to said frame, comprising a torsion rod having endswhich are out-of-round in cross section and arranged generally inalinement with v said axis, a socket member fast .to the hub of saidcrank arm and having an oversize out-of-round socket fitting oneout-of-round end of said torsion rod, an anchoring socket member fast tosaid frame and having an oversize out-of-round socket fitting the otherout-of-round end of said 16 torsion; rodand-mwns pinnin :each iofzrsa-idsocket members to the correspondinge Said torsion rod, and permitting alimited rotative movement of said torsion rod relative to .said socketmember.

3. A vehicle spring suspension for connecting the frame and wheeled axleof a vehicle, comprising a normally generall horizontal crank armfulcrumed on said frame on a generally horizontal axis extendingtransversely of said axle and free to movelengthwise of said axis,a-shackle movably connecting the free end of said crank .arm with saidaxle, andmeans for restraining fitting. the other out-of-round end ofsaid torsion rod and means pinning each-of said socket members to thecorresponding end of said torsionrod, and permitting a limited rotativeand axialmovement of said torsion rod relative to said socket member.

. 4. A vehicle spring suspension for connecting the frame and wheeledaxle of a vehicle, com- ,prising .a normally generally horizontal crankarm fulcrumed on said frame on a generally horizontal axis extendingtransversely of said .axle and free to move lengthwise of said axis,

a shackle movably connecting the free end,;of said crank arm with saidaxle, and means for restraining rotative and axial movementof said crankarm relative to said frame, comprising a torsion rod having ends whichare out-of-round ,in cross section and arrangedcgenerallyinalineof saidsocket members to the corresponding end of said torsion rod, andpermitting a limited rotative and axial movement of said torsion rodrelative to said socket member comprising a cross pin snugly fitted in ahole in each socket member and extending into an oversized hole in saidcorresponding end of said torsion rod.

5. A vehicle spring suspension for connecting the frame and wheeledaxleof a vehicle, comprising a normally generally horizontal crank armhaving a hub fulcrumed on said frame on a generally horizontal axisextending transversely of said axleand free .to movelengthwise of saidaxis, a shackle mova'bly connecting the free end of .said crank arm withsaid axle, a torsion rod having ends which are out-of-round in crosssection and said torsion rod being arranged generally in alinement withsaid axis, a socket member fast to said hub of said crank arm and havingan oversize out-of-round socket fitting one outof-round end of saidtorsion rod, an anchoring socket member fast to said frame and having anoversize out-of-round socket fitting the otheroutof-roun'd end of saidtorsion rod, the friction 'of said out-of-round ends of said torsion rodnormally preventing axial displacement of said hub, and a stop fast tosaid frame and in line with 17 the end of said hub to further preventaxial displacement of said hub.

6. A vehicle spring suspension for connecting the frame and wheeled axleof a vehicle, comprising a normally generally horizontal crank armhaving an elongated tubular hub, a pair of bearings for said tubular hubmounted in spaced relation on said frame and supporting said hub onagenerally horizontal axis extending transversely of said axle, one ofsaid bearings being arranged adjacent one end of said tubular hub, ashackle movably connecting the free end of Said crank arm with saidaxle, a torsion rod having its live end extending through said one endof said tubular hub to the opposite end thereof, means operativelyconnecting the live end of said torsion rod to the said opposite end ofsaid tubular hub, means anchoring the dead end of said torsion rod onsaid frame, a member fast to said one of said bearings, and a rubbersleeve carried by said 18 member and engaging the adjacent portion ofsaid torsion rod to prevent whipping thereof.

ALBERT F. HICKMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,160,862 Hickman June 6, 19392,245,809 Ol1ey June 17, 1941 2,256,069 Wagner Sept. 16, 1941 2,307,772Duffy Jan. 12, 1943 2,328,868 Weiss Sept. 7, 1943 2,395,183 Holmstrom etal. Feb. 19, 1946 2,413,212 Brown Dec. 24, 1946 2,428,160 Holmstrom etal. Sept. 30, 1947

